DEERFIELD — Walgreen completed its purchase of European health and beauty retailer Alliance Boots and on the final day of 2014, the combined company’s stock will begin trading under the ticker symbol “WBA.”

The nation’s largest drugstore chain said Wednesday that shares long traded under the symbol “WAG,” have been converted to the ticker symbol of the new company called Walgreens Boots Alliance Inc. Walgreen is now a subsidiary.

The deal’s completion comes a couple days after Walgreen shareholders voted in favor of the acquisition. Walgreen bought a 45 percent stake in Alliance Boots, which runs the United Kingdom’s largest pharmacy chain, in 2012 for about $6.7 billion in cash and stock. The company said in August that it would buy the remaining stake for roughly $16 billion in additional cash and stock.

The combined company, which is based in Deerfield, Illinois, has more than 12,800 stores and 340 pharmaceutical distribution centers globally.

Walgreen shares closed at $76.05 Tuesday and have climbed 32 percent so far this year, more than doubling the advance of the Standard & Poor’s 500 index.